Flex httpService 用Ip访问不了

var httpLogin:HTTPService = new HTTPService();
httpLogin.url="http://192.168.66.15/sys/user/login.action";
httpLogin.resultFormat="text";
httpLogin.method="post";
httpLogin.showBusyCursor=true;

httpLogin.request={userName:this.txtuserName.text,password:this.txtpassword.text,checkCode:this.txtCode.text};
httpLogin.addEventListener(ResultEvent.RESULT,getuser_result);
httpLogin.addEventListener(FaultEvent.FAULT,getuser_fault);
Alert.show(httpLogin.url);
httpLogin.send();

把192.168.66.15改成localhost就可以，请高手帮忙！